initialize(self)

This is called by the ComponentHolder after it set the instance. Use
this to initialize any needed infrastructure. When this is called, it is
guaranteed that all other components this one has a dependency on have
been added, but initalize may not have been called on them, only
__init__. It is only called after construction, not on load().

save(self,
db)

load(self,
db,
worldid)

This does on load what __init() and initalize() together do on
constructions at runtime. Has to set up everything that is not setup in
__init__(). Note that on loading __init__() is called with the data
needed by the component through get_instance(), but initialize() is not,
so any work needed for loading as well should be moved to a separate
method and called here.